The cutting of metals and other hard materials is often carried out with the use of a cutting tool to provide a desired shape, size or surface to the workpiece. When cutting these hard materials, frictional heat can bum the cutting tool and make the machined surface of the workpiece rough. Furthermore, thermal expansion lowers the accuracy of the shape and the size of the workpiece and the tool, thereby causing various other problems. To help alleviate the above problems, a cutting fluid is often employed during cutting.
Oils are commonly used as a cutting fluid when cutting metals and other hard materials. One disadvantage of using a straight oil as a cutting fluid is that it usually has to be used at low temperatures because high temperatures can cause the production of fire and smoke. To help overcome this problem, an oil-water emulsion cutting fluid having sufficient lubricity and cooling properties, can be used as a cutting fluid.
Unfortunately, cutting fluids, especially water-based cutting fluids, are susceptible to bacteria and other microbial propagation. Bacterial colonies often result in unpleasant odors, deterioration of the cutting fluid, and serious health hazards. In general, there are two types of bacteria that grow in cutting fluids: aerobic, which multiply in the presence of oxygen, and anaerobic, which propagate in the absence of oxygen. While the anaerobic types can result in unpleasant odors through the production of hydrogen sulfide, they typically do very little actual damage to cutting fluid itself. However, the aerobic type seriously degrades fluids, causing corrosion inhibition and loss of lubricity. Furthermore, the bacterial lifecycle while “eating” the fluid concentrate also results in the deposition of various acids and salts. This can cause extensive rusting/corrosion of both moving machine parts and the material being machined.
To prevent these accompanying problems, biocides have been added to cutting fluids. In practice however, these agents are of limited usefulness. In addition to costing more money, there are limits on the amount of biocide which can be incorporated into the cutting fluid. Furthermore, these agents are often ineffective, degrade over time, and replacing them can be expensive. In addition, these agents and substances often lower the quality of the cutting fluid.
Accordingly, there is a need in the art for an effective and new method of treating cutting fluids, that can provide uniform protection, or substantially uniform protection with time, without the use of large amounts of biocides.